Waiting for Connection

[D]

I am trying to do the following using Python and Tkinter:

1)  Display a window with 1 button
2)  When user clicks the button, Python attempts to call a function
that opens a socket and listens for a connection - what I want to do
is, if the socket has been successfully opened and the system is
waiting for a connection, to turn the button green.

The problem I'm having is when the button is clicked, the color never
changes and the application "locks up" until the remote end connects
and disconnects.  Where can I put the button configuration statement so
that it will turn green to indicate the socket was opened successfully?
 Thanks!